2017 was our 20th year online!

Welcome to the Piano World Piano Forums
Over 2.9 million posts about pianos, digital pianos, and all types of keyboard instruments
Join the World's Largest Community of Piano Lovers (it's free)
It's Fun to Play the Piano ... Please Pass It On!

Shop our online store for music lovers
SEARCH
Piano Forums & Piano World
(ad)
Petrof Pianos
Petrof Pianos
(ad)
Pianoteq
PianoTeq Karsten Collection
(ad)
Piano Life Saver - Dampp Chaser
Dampp Chaser Piano Life Saver
Who's Online Now
37 members (FrankCox, AZNpiano, chopinetto, Charles Cohen, cjmack, CyberGene, DreamPiano80, 11 invisible), 389 guests, and 212 robots.
Key: Admin, Global Mod, Mod
(ad)
Estonia Pianos
Estonia Pianos
Previous Thread
Next Thread
Print Thread
Hop To
String behaviour on a real piano
#2987675 06/04/20 04:33 AM
Joined: Jun 2020
Posts: 7
T
Junior Member
OP Offline
Junior Member
T
Joined: Jun 2020
Posts: 7
Hi there! I am a digital piano player and I would really like to know how a real piano string behaves. My question: If you play a loud note and sustain it and then you play the same note a bunch of times but very quiet and in a certain pattern will the first loud tone be sustained the whole time you play the same note quietly or at some point the loud tone at the beginning gets silenced (muted)?

You might be wondering what's the point of the question? Well, my digital piano f-140r from Roland drops the first loud tone after some presses on the same key. This all hapens while holding down the sustain pedal. This is not a polyphony problem-the f-140r has a 128 note polyphony and I think it can take more than a few key presses before dropping a note.

(ad int) Petrof Pianos
Petrof Pianos
Re: String behaviour on a real piano
Teodor2002 #2987690 06/04/20 06:12 AM
Joined: Mar 2019
Posts: 56
D
Full Member
Offline
Full Member
D
Joined: Mar 2019
Posts: 56
I guess that's an interesting question from a digital piano perspective. Depending on the algorithms set, the digital is either cycling the triggering of new instances of the samples of multiple voices of polyphony, (most likely), or retriggering the same sample (not very common these days). Using "round robin" techniques, the digitals sometimes trigger slightly differing versions of a velocity sample to avoid the identical flanging effect that can be caused.

Note repetition in a real piano response is happening in a very different way to a digital piano.
In an acoustic piano, note repetition simply continues inputting energy into the string to keep it excited by the repetitive action of the hammer striking the string, This just keeps replenishing the energy that keeps building on the existing excitation, which also replenishes the state of the decaying harmonic emissions, and the hammer strike being part of the retrigger sound, so the string decay is the same string vibration event with repetitively added energy, ......to oversimplify it.

Others may contribute in a different way to describe what's happening, but this is my way which comes to mind smile

Last edited by Deltajockey; 06/04/20 06:21 AM.

The companions I can't live without.........

Kawai GL30 Acoustic Grand. Kawai MP11SE, Korg Kronos 2-88
Re: String behaviour on a real piano
Teodor2002 #2987699 06/04/20 06:49 AM
Joined: May 2018
Posts: 699
500 Post Club Member
Offline
500 Post Club Member
Joined: May 2018
Posts: 699
In an acoustic it gets REALLY complicated.

When the hammer hits an already vibrating string, the hammer will function both to set off another sequence of vibrations and act as a damper during the time of contact with the string (although with quite different characteristics than the actual dampers). The overall effect will be the introduction of a phase shift in the string (because it is unlikely that the new hammer blow will be in phase with the vibrations already present).

This means that the existing vibration is changed, partly dampened, partly enforced.

But it gets worse: by the time of the second hammer blow, the sound board is in full swing (literally), and the change in the vibration of the string will be transfered (after a time lag) to the sound board, the vibration of which will therefore also be changed. The sound board is what is actually heard.

Mathematically it would be maddening to calculate the effects in minute detail.


Roland FP-30, Roland E-28
Pianoteq 6.5 (Bechstein DG, Grotrian, Steinway D, K2), Garritan CFX Lite, Production Voices Estate Grand
Re: String behaviour on a real piano
Teodor2002 #2987700 06/04/20 06:51 AM
Joined: Jul 2012
Posts: 42
S
Gold Subscriber
Full Member
Offline
Gold Subscriber
Full Member
S
Joined: Jul 2012
Posts: 42
But first of all it depends if, and if yes, how much the damper pedal is involved.

Re: String behaviour on a real piano
QuasiUnaFantasia #2987705 06/04/20 07:20 AM
Joined: Feb 2018
Posts: 766
G
500 Post Club Member
Offline
500 Post Club Member
G
Joined: Feb 2018
Posts: 766
Originally Posted by QuasiUnaFantasia
In an acoustic it gets REALLY complicated.

When the hammer hits an already vibrating string, the hammer will function both to set off another sequence of vibrations and act as a damper during the time of contact with the string (although with quite different characteristics than the actual dampers). The overall effect will be the introduction of a phase shift in the string (because it is unlikely that the new hammer blow will be in phase with the vibrations already present).

This means that the existing vibration is changed, partly dampened, partly enforced.

But it gets worse: by the time of the second hammer blow, the sound board is in full swing (literally), and the change in the vibration of the string will be transfered (after a time lag) to the sound board, the vibration of which will therefore also be changed. The sound board is what is actually heard.

Mathematically it would be maddening to calculate the effects in minute detail.

Especially if you aren't satisfied with this 'simple' case and want to also model sympathetic vibrations in other strings, I wonder what phase those would be :-)

Re: String behaviour on a real piano
Teodor2002 #2987770 06/04/20 10:34 AM
Joined: Jun 2020
Posts: 7
T
Junior Member
OP Offline
Junior Member
T
Joined: Jun 2020
Posts: 7
Woow...Thanks for all your information, you all really made my day. It's awesome to actually understand the physics of a real piano. So to wrap it up- is this a normal behaviour for a digital piano? Should I be concerned about the silenced note or is it just a Roland feature which is trying to simulate an acoustic piano?

Re: String behaviour on a real piano
Teodor2002 #2987777 06/04/20 10:47 AM
Joined: May 2013
Posts: 2,517
Bronze Subscriber
2000 Post Club Member
Offline
Bronze Subscriber
2000 Post Club Member
Joined: May 2013
Posts: 2,517
Originally Posted by Teodor2002
Woow...Thanks for all your information, you all really made my day. It's awesome to actually understand the physics of a real piano. So to wrap it up- is this a normal behaviour for a digital piano? Should I be concerned about the silenced note or is it just a Roland feature which is trying to simulate an acoustic piano?
I suggest you ask the question about your Roland in the digital section of this forum.
Ian


I'm all keyed up
2016 BlĆ¼thner Model A
Re: String behaviour on a real piano
Teodor2002 #2987787 06/04/20 11:05 AM
Joined: Feb 2018
Posts: 766
G
500 Post Club Member
Offline
500 Post Club Member
G
Joined: Feb 2018
Posts: 766
Originally Posted by Teodor2002
Woow...Thanks for all your information, you all really made my day. It's awesome to actually understand the physics of a real piano. So to wrap it up- is this a normal behaviour for a digital piano? Should I be concerned about the silenced note or is it just a Roland feature which is trying to simulate an acoustic piano?

Well, it isn't 'normal' behaviour for a real piano either. Different pianos will behave differently, in the case you give even the same piano would seem to behave differently from note to note depending on the string phase when it is re-struck.

What you have observed on the Roland does to me seem more likely a limitation of its design rather than a feature. Did you find a piece of music where this limitation is displayed?

Re: String behaviour on a real piano
Teodor2002 #2987819 06/04/20 12:19 PM
Joined: Dec 2012
Posts: 5,613
C
5000 Post Club Member
Online Content
5000 Post Club Member
C
Joined: Dec 2012
Posts: 5,613
Originally Posted by Teodor2002
Woow...Thanks for all your information, you all really made my day. It's awesome to actually understand the physics of a real piano. So to wrap it up- is this a normal behaviour for a digital piano? Should I be concerned about the silenced note or is it just a Roland feature which is trying to simulate an acoustic piano?

FWIW --

Pianoteq (a "modelled" VST) does a pretty good job of simulating an acoustic piano's behavior:

. . . If you hit a key with "ff", followed by a series of "p",

. . . the original "ff" keeps sounding,

. . . and the "p" strikes add to the sound.

It sounds like a cymbal roll. Most DP's (e.g. my PX-350) don't understand how to do that.

To make it work well, you must use a 3-sensor action (which the PX-350 has), and _not_ completely lift the key, between strikes.

I don't think that's possible, with a two-sensor action.

With a 3-sensor action, you can generate several MIDI "note-on" events, without any intervening "Note off" events. You do that by not letting the key rise up all the way, but re-striking when it's halfway up.

It makes a difference, because the "note off" event is what tells the sound generator to lower the (virtual) damper and stop the sound.

If the F140 has a two-sensor action, it's not surprising that it should respond as you describe:

. . . When it gets the "note on / ff" event, it triggers the
. . . note at "ff" volume;

. . . when it gets the "note off" event, it drops the damper,
. . . . and the note decays;

. . . when it gets the "note on / p" event, it re-triggers the
. . . sample at "p" volume,

. . . and continues to decay the original note, even though
. . . the (virtual) damper is no longer on the (virtual) string.

If you look back, in the "Digital Pianos" forum, you'll find a
very long "DPBSD" (digital piano bull-[censored] detector) thread. It's a history of tests of DP's, and how well they simulate acoustic-piano behavior.

They've gotten better over the years, but they're still not perfect.


. Charles
---------------------------
PX-350 / microKorg XL+ / Pianoteq / Lounge Lizard / EV ZXA1 speaker
Re: String behaviour on a real piano
Charles Cohen #2987885 06/04/20 03:07 PM
Joined: Jun 2019
Posts: 375
O
Full Member
Offline
Full Member
O
Joined: Jun 2019
Posts: 375
Originally Posted by Charles Cohen
Originally Posted by Teodor2002
Woow...Thanks for all your information, you all really made my day. It's awesome to actually understand the physics of a real piano. So to wrap it up- is this a normal behaviour for a digital piano? Should I be concerned about the silenced note or is it just a Roland feature which is trying to simulate an acoustic piano?
. . .

If the F140 has a two-sensor action, it's not surprising that it should respond as you describe:

. . .

Charles, I hadn't considered the number of sensors before reading this (thank you).

The first thing that came to my mind was the fact that a F140r is sampled - my thoughts were, initially, there are only so many events that the samples can cater for? My fully modelled DP behaves in a manner similar to your VST description (but it has three sensors, so it did leave me wondering).

Each strike of a key could add energy to an already vibrating string... I am now wondering how on earth that could be calculated and executed somewhat accurately on a sampled digital piano? Would the hammer strike and subsequent change in sound/volume need to be sampled/played back seperately? I'm intrigued. šŸ¤“


Learning to play. Consciously incompetent, which apparently is a good starting point. smirk
Re: String behaviour on a real piano
OscarRamsey #2988336 06/06/20 04:08 AM
Joined: Jun 2020
Posts: 7
T
Junior Member
OP Offline
Junior Member
T
Joined: Jun 2020
Posts: 7
The f-140r has a triple sensor action and 128 polyphony.

Re: String behaviour on a real piano
Teodor2002 #2988338 06/06/20 04:13 AM
Joined: Jun 2020
Posts: 7
T
Junior Member
OP Offline
Junior Member
T
Joined: Jun 2020
Posts: 7
Just a really quick update: The initial note drop gets even more noticeable when playing the number 5 piano voice which is piano layered with strings. I will record a test to highlight the issue and let you guys listen to that.

Re: String behaviour on a real piano
Teodor2002 #2988348 06/06/20 05:18 AM
Joined: Jun 2020
Posts: 7
T
Junior Member
OP Offline
Junior Member
T
Joined: Jun 2020
Posts: 7
Piano 5 (Piano layered with strings) sample: https://drive.google.com/file/d/1Ek8rUfNgDxC891DhAL6NpVsi_GhR00D-/view?usp=sharing

Piano 1 (Default piano, the best one): https://drive.google.com/file/d/1u_GjuRIFf5IYg_APo7dn1ZhgngAup0Fa/view?usp=sharing

The note drop is not caused by the sustain pedal. I was holding it the whole time (just lifting it when necessary to avoid the annoying echo we all know about).

Tell me what you think about both of them. The note drop can be noticed on both pianos when playing a C#1 and repeating it (May it be, by Enya)

Re: String behaviour on a real piano
Charles Cohen #2988356 06/06/20 06:42 AM
Joined: Feb 2018
Posts: 766
G
500 Post Club Member
Offline
500 Post Club Member
G
Joined: Feb 2018
Posts: 766
Originally Posted by Charles Cohen
If the F140 has a two-sensor action, it's not surprising that it should respond as you describe:

. . . When it gets the "note on / ff" event, it triggers the
. . . note at "ff" volume;

. . . when it gets the "note off" event, it drops the damper,
. . . . and the note decays;

But it shouldn't get a 'note off' event, even on a two sensor keyboard, when played as the OP describes i.e. the sustain pedal held down.

Re: String behaviour on a real piano
Teodor2002 #2989411 06/09/20 12:56 PM
Joined: Feb 2020
Posts: 57
M
Full Member
Offline
Full Member
M
Joined: Feb 2020
Posts: 57
Originally Posted by Teodor2002
You might be wondering what's the point of the question? Well, my digital piano f-140r from Roland drops the first loud tone after some presses on the same key. This all happens while holding down the sustain pedal. This is not a polyphony problem-the f-140r has a 128 note polyphony and I think it can take more than a few key presses before dropping a note.

My Yamaha Motif synth does the same. Although it has a high polyphony limit, it only allows up to 4 strikes on the same key to sound. In other words, the overall limit isn't used for a single note.
Hitting a note at ff, then followed by p or pp, will cause the initial ff note to be turned off when you hit the fourth soft press. I haven't experimented with combined sounds yet.

Now here's the interesting part:
I did the experiment with my acoustic piano (Kawai GX-6) using C2, recorded the waveform on my scope, then took amplitude measurement samples at 1-sec intervals for 10 sec. Here are the results:

----- Natural -- Decay with
T ---- Decay -- pp rep's

0 ---- 310 ------ 308
1 ---- 133 ------ 130
2 ----- 71 ------- 79
3 ----- 48 ------- 54
4 ----- 35 ------- 40
5 ----- 26 ------- 34
6 ----- 24 ------- 28
7 ----- 18.7 ----- 19.2
8 ----- 17.4 ----- 17.5
9 ----- 13.5 ----- 16.8
10 ---- 15.2 ------ 15

So although the repeated hammer strikes might be expected to dampen some of the initial energy, it turns out that the net effect is to add a little energy and the overall decay is slightly slower. (Note the amplitude of the repetitions was about 15-18 so that is the lowest level it can fall to, for that run.)
The unexpected slight rise at 10 sec for the natural decay is just the effect of beats.


First love: Kawai GX-6
Yamaha Motif XF8
Tektronix MSO4104

Moderated by  Ken Knapp, Piano World 

Link Copied to Clipboard
What's Hot!!
News from the Piano World
Where Did The Buttons Go?!
----------------------
Our April 2020 Newsletter Available Online Now...
The Piano World During the Pandemic!
----------------------
Posting Pictures on the Forums
-------------------
Forums RULES & HELP
-------------------
ADVERTISE on Piano World
(ad)
Best of Piano Buyer
 Best of Piano Buyer
(ad)
Faust Harrison Pianos
Faust Harrison 100+ Steinway pianos
Download Sheet Music
Virtual Sheet Music - Classical Sheet Music Downloads
New Topics - Multiple Forums
Kawai GL-10 vs. Hailun 150SE
by cjmack - 07/14/20 01:24 AM
Modern Alternatives to the Metronome
by navindra - 07/13/20 08:10 PM
Eleanor Sokoloff RIP
by pianoloverus - 07/13/20 04:15 PM
Winter NAMM 2021 - Proceed or Cancel?
by PianoManChuck - 07/13/20 03:55 PM
Forum Statistics
Forums41
Topics200,239
Posts2,980,396
Members97,760
Most Online15,252
Mar 21st, 2010
Please Support Our Advertisers


Faust Harrison 100+ Steinways

Dampp Chaser Piano Life Saver

 Best of Piano Buyer

PianoTeq Bechstein
Visit our online store for gifts for music lovers

Virtual Sheet Music - Classical Sheet Music Downloads



 
Help keep the forums up and running with a donation, any amount is appreciated!
Or by becoming a Subscribing member! Thank-you.
Donate   Subscribe
 
Our Piano Related Classified Ads
| Dealers | Tuners | Lessons | Movers | Restorations | Pianos For Sale | Sell Your Piano |

Advertise on Piano World
| Subscribe | Piano World | PianoSupplies.com | Advertise on Piano World |
| |Contact | Privacy | Legal | About Us | Site Map | Free Newsletter |


copyright 1997 - 2020 Piano World ® all rights reserved
No part of this site may be reproduced without prior written permission
Powered by UBB.threads™ PHP Forum Software 7.7.4